title: Von Willebrand factor, diabetes mellitus and retinopathy.
abstract: Von Willebrand factor (VIII: vWf) is a glycoprotein which is essential for normal platelet adhesion to vascular subendothelium, particularly at the high shear rates encountered in small blood vessels. VIII: vWf is distributed in plasma, platelets and subendothelium, though the contributions of each pool to normal hemostasis is unknown. Raised plasma of VIII: vWf have been frequently described in association with diabetes, the highest concentrations being found in patients with retinopathy. In addition, concentrations of VIII: vWf appear to be influenced by the degree of metabolic control of the diabetics, particularly high levels being found during diabetic coma. Plasmatic concentrations of VIII: vWf greater than normal have not been shown to result in increased platelet adhesion or aggregation, so that is seems unlikely that the high levels of plasmatic VIII: vWf contribute directly to the pathogensis of retinopathy. On the other hand, increases in VIII: vWF during episodes of poor metabolic control could be evidence of reversible injury to the vascular endothelium, whereas stable, high concentrations may indicate the presence of microangiopathy.
mesh_terms: D001779:Blood Coagulation Factors / Q000502:physiology*; D003920:Diabetes Mellitus / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005169:Factor VIII / Q000502:physiology; D006487:Hemostasis; D006801:Humans; D010974:Platelet Aggregation; D014841:von Willebrand Factor / Q000502:physiology*
chemical_list: D001779:Blood Coagulation Factors; D014841:von Willebrand Factor; D005169:Factor VIII